ABSTRACT Determining what and how much each environmental factor affects pregnancy is crucial to the sustainability and management of beef cow herds. The study evaluated through logistic regression the effect of environmental variables on the increase or reduction in the pregnancy rate of beef cows. The average pregnancy rate in the cows was 73 %, with an average age for the herd of 3.7 years. An increase in age of one year represented a 30 % increase in pregnancy, while a reduction of one year reduced the odds of pregnancy in the cows by 23 %. During the lactation period, an extra seven days’ lactation reduced the odds of pregnancy by 12 %. For every seven days that weaning was brought forward, the cows’ pregnancy odds increased by 14 %. An increase of 0.1 kg in average daily gain represented an increase of 17 % and 15 % in the odds of pregnancy during the first 60 days post-partum and 60 days to the end of the reproductive period. On the other hand, the loss of 0.1 kg in average daily gain resulted in a 14 % and 13 % reduction in the cows’ pregnancy odds, respectively. Factors such as age, the precocity of calving in the calving season, the time the calf remains with the cow and better performance in cows between calving and the end of the mating are strategies that increase the chances of pregnancy in beef cows. herds 7 37 3 3. years 2 period 1 forward 01 0 0. 6 postpartum post partum hand respectively season

ABSTRACT In the last decade, other quality attributes have emerged as the main aspects that impact pork consumers acceptance, such as environmentally friendly production, nutritional value, and animal welfare. This study applies a Check-All-That-Apply (CATA) questionnaire for sensory characterization of loins from genetically lean immunocastrated male pigs fed diets containing either a standard commercial diet with 1.5 % soybean oil (control) or 3 % oil from either soybean oil (SO), canola oil (CO), or fish oil (FO) during the growing-finishing phases. Twenty CATA attributes for loin samples were generated. We interviewed 101 consumers to select all the CATA terms that they considered suitable to characterize sensory attributes of longissimus lumborum muscle samples of pigs from each dietary treatment. The CATA results indicated differences among pork loin samples depending on the source and inclusion level of dietary oil. Loins from pigs fed 3 % SO were characterized by a higher frequency of the “juicy texture” attribute (p < 0.05) and a lower frequency of the “dry texture” attribute (p < 0.05) compared to loins from 3 % FO-fed pigs. Moreover, loins from pigs fed 3 % SO had a lower citation frequency of the “tasteless” attribute (p < 0.05) compared to loins from 3 % FO-fed pigs. The attributes “cooked pork meat-like taste”, “juicy texture”, “tender texture”, and “brightness” were placed close to the overall liking. “Tender texture”, “juicy texture”, “pork meat-like” (odor and taste), and “cooked pork meat-like taste” attributes were considered drivers of liking. Feeding genetically lean immunocastrated male pigs with diets containing 3 % SO may be advisable from a pork sensory quality perspective.

ABSTRACT: Heterosis plays an important role on yield and profitability of beef production systems. This study evaluates the morphometrics of purebred Nellore (N) and Charolais (C) animals and of the second (G2) and third (G3) generations of their alternating crosses, regarding the effects of genetic group and heterosis from birth to 365 days of age. The experiment comprised 159 calves (C = 29, N = 22, G2 - 3/4C 1/4N = 21, 3/4N 1/4C = 9, G3-5/8C 3/8N = 44 and 5/8N 3/8C = 34). The foreshank girth (FG), thoracic girth (TG), body length (BL), and hip height (HH) were measured after birth, and at 63, 210, and 365 days of age, and the total increases were calculated. The Charolais animals had greater FG, TG, and BL values than Nellore, while the latter had greater HH. For the offspring generations, the predominance of Charolais genes in the genotypes resulted in greater measurements for FG and TG in G2, whereas the predominance of Nellore genes resulted in higher HH values in both generations. The crossbred animals had greater values for all measurements than the purebreds, with more significant differences in FG, TG, and BL compared to Nellore purebreds and in HH compared to Charolais. Charolais animals show higher values for muscularity; while, Nellore animals are taller. Crossbred animals show greater development compared to purebreds, indicating a significant effect of heterosis.

Zebu cattle fed high concentrate diets may present inconsistent performance due to the occurrence of metabolic disorders, like acidosis. The isolated use of ionophores and virginiamycin in high grain diets can improve animal performance and reduce the incidence of such disorders, but recent studies suggested that their combination may have an additive effect. Thus, 72 Nellore steers, 389 ± 15 kg initial body weight (BW), were confined and fed for 79 days to evaluate the combination of virginiamycin and salinomycin on performance and carcass traits. Animals were allocated to a randomized complete block design by BW, in a 2 × 2 factorial arrangement of treatments, with two concentrate levels (73 and 91 %) and two virginiamycin levels (0 and 15 mg kg-1), and salinomycin (13 mg kg-1) included in all diets. The interaction was not significant (p > 0.05). Dry matter intake (DMI), average daily gain (ADG), gain-to-feed ratio (G:F), starch consumed, and fecal starch content were higher (p < 0.05) for the 91 % concentrate treatment. These animals also had higher (p < 0.05) hot carcass weight and dressing percentage. Virginiamycin-treated animals showed lower DMI, but ADG and G:F did not differ (p > 0.05) between treatments. Starch consumed and estimated dietary net energy for maintenance (NEm) and gain (NEg) were higher (p < 0.05) for virginiamycin-treated animals, with no substantial effects on carcass traits. The inclusion of virginiamycin in finishing diets containing salinomycin reduced DMI while maintaining ADG and improving NEm and NEg, suggesting an additive effect of virginiamycin and ionophores, but without affecting carcass quality.

The β-adrenergic agonist ractopamine is increasingly used in the swine industry due to higher consumer demand for leaner pork products. Redirecting nutrients to favor leanness rather than fat deposition, ractopamine improves growth and carcass traits of finishing pigs. However, the impact of this agonist on pork quality is not clearly defined. Understanding the biological effects of dietary ractopamine dose, treatment period, lysine levels, and the lysine to metabolizable energy ratio will help pork producers achieve improvements in animal performance, carcass leanness, and economic efficiency in swine production systems.